Electric power lift



June 1, 1943. o, H, sHENsToNE ELECTRIC POWER LIFT 3 sheets-sheet 1 Filed April 25, 1941 ATTORNEY June 1, 1943. o. H. HENsToNE 2,320,953

' ELECTRIC POWER LIFT Filed April 25, 1941 3 Sheets-Sheet 2 -IN V EN TOR.

faQ/)EY June l, 1943. o H. sHENsToNE ELECTRIC POWER LIFT Filed April 25, 1941 3 Sheets-Sheet `3 INVENTOR. 05am/yah. Hfmso/yf BY Arroz/vnf Patented June l, 1943 l ELECTRIC POWER LIFT Osborne H. Shenstone, Toronto, Ontario, Canada', assigner to Massey-Harris Company Ltd.,

Toronto, Ontario, Canada A 1 Canada,

a company of Application April 25, 1941, Serial N0. 390,305

8 Claims.

The present invention relates to what-is commonly called power lifts wherein implements or other direct coupled machines may be lifted or returned to their operating position by power derived from the electric self starting system of a tractor. l

Modern tractors are equipped with self starters having storage batteries. Therefore the source of electric power for my improved lift, when applied to a tractor is available. It will be understood that my improved lift may be applied to other sources of power and used for other purposes, for example, vehicle jacks, servo brakes,\ and actuators for dump truck bodies and the like.

An object of the present invention is to provide means whereby the lifting and return movement may be controlled by the oporator and whereby the length of stroke in either direction will also be under the control of the operator.

A further object of my invention is to provide 2 a power lift which is simple, light, durable, easily installed and easily manufactured at moderate cost.

To these and other useful ends, my invention consists of parts, combinations of parts, or their equivalents, and mode of operation, as hereinafter set forth and claimed and shown in the accompanying drawings in which:

Fig. 1 is a longitudinal sectional view of the main operating parts of my device.

Fig. 2 is an enlarged fractional longitudinal sectional view of the main operating parts of my device taken at right angles to that shown in Figure 1. Y

Fig. 3 is a sectional view taken on line 3 3 of Figure 2.

Fig. 4 is a sectional view taken on line 4--4 of Figure 2.

Fig. 5 is a diagrammatic drawing of my complete device less the housing and reversing switch but showing a fraction of the motor and some of the parts broken away.

Fig. 6 is a diagrammatic drawing of the entire electric system, showing the cam which operates the starting and stopping switch.

As thus illustrated, the frame of my device is designated in its entirety by reference character A and the motor by reference character B. The

controlling or starting and stopping means which are mechanically connected to the device are designated in their entireties by reference character C and the reversing switch is designated in its entirety by reference character D.

Frame A is provided preferably with a circular in cross section housing I0 adapted to receive the motor B which is held in the frame by means of set screws as illustrated. I provide a frame extension I2 which preferably encloses the exposed end of member B and being secured to housing I0 by means of set screws I3.

It will be seen that by removing setscrews I3, member I2 may be removed from frame A and by loosening set screws II, the motor may be removed from housing I0.

I provide an apertured bracket I4 for connection to the frame of the tractor or to any other frame or stationary anchor. A shaft I5 is threaded as at I6 from its forward end to near a. bearing |1 which is adapted to rotatably carry shaft I5 and take the end thrust from this shaft.

Motor shaft I8 is operatively connected to shaft I5 by means of a, clutch I9. This clutch is provided with means whereby no end thrust willl be transmitted to shaft I8 from shaft I5. i

A sleeve 20 is slidably mounted in the forward end 2| of housing A and is provided with an internal screw thread 22 which engages thread I6. The protruding end of sleeve 20 is provided with an apertured bracket 23 which is adapted to be connected to the part to be moved or its connection to this part. l

Sleeve 20 is provided with a key projection 24 (see Figure 3) adapted to be slidably engaged by a keyway 25 in member 2 I; thus' the sleeve is prevented from turning but is left free to move longitudinally in member 2| when the motor is turned in one direction or the other because of the engagement between threads 22 and lli.l 'I'hus when member Il is anchored to the frame of the tractor, or otherwise, and the motor is turned in either direction, member 23 will be caused to move longitudinally of the frame and transmit power from the motor to the implement or device lifted or operated. i

I provide means for manually controlling the direction of rotation of the motor and the longitudinal movement of sleeve 20in the following manner:

A projection 29 is provided onme'mber 2| having a keyway 30. A controlling bar 3| `is `slidably mounted in member 30 and having a projection 32 at its forward end and a projection 33 aI; its rear end. Sleeve 20 is provided withy a projection 34 (see Figures 2 and 3) which is slidably mounted within keyway 30 and .is `positioned between members 32 and.33.

Generally my power lift is designed so member 23 may be moved back and forth approximately l5 inches. Members 32 and 33 'are spaced about 5 inches apart for a purpose which will hereinafter appear. I provide a pin 35 (see Figures 2 and 4) having hingedly connected lthereto a link `this connection wherein a bracket 39 is operatively connected to arm 31 by means of a rod 40. Members 39 and 40 operate similar to members 35 and 36. Members 39 and 48 are shown in order to make clear the function of the connection between members'3l and 31. 'I'he object of these connections is to oscillate shaft 38 by means of the reciprocation of member 3| caused by the longitudinal movement of sleeve 28.

I provide a spring 45 adapted to move shaft 38 and urge the free end of arm 31 toward the motor. One end of this spring may be anchored to shaft 38 as shown in Figure 5 or to member 56 as shown in Figure 4. The other end is preferably secured to the housing of the device as at 45'. This spring 45 is prevented from moving lever 31 its full travel toward the motor by means of a spring 46 (see Figure l) This spring necessarily is considerably stronger than spring 45; thus when projection 34 contacts projection 33, member 28 may then complete its travel so as to turn shaft 38 and shut off the motor in the following manner:

I provide a two contact switch 41 which is conventional and is carried by an arm 48 having a hub 49 which is rotatably mounted on shaft 38. I provide a sector 58 having a manually operated lever 5| which is pivoted to member 50 as at 52, the sector and lever having means (not shown) whereby the lever may be moved to and held in any desired position relative to the sector.

I provide a bowden cable 53 having a connection to lever 5|as at 54 and a connection to arm 48 as at 55 so member 41 may be swung around the axis of member 38. Iprovide a sector 56 which is secured to shaft 38 by means of a screw 56', the sector having a short intermediate surface 51, a lower surface 58 and a higher surface 59, each of these three surfaces being on a radius with shaft 38.

A medial lever 69 is provided having a projection 60' (see Figures 4 and 5) which yieldingly contacts surfaces 51, 58 and 59 and having contact points 6| so when member 68' is in contact with surface 58, a point 6I will be in contact .with

a point 62 and when member 60' is on surface 51, this contact will be broken. Furthermore when member 68' is in contact with` surface 53, member 6| will engage contact point 63; thus member 68' must be yieldingly held toward member 56. In devices of the class, member 68 is generally made from flat spring stock and shaped so member 68 isv yieldingly held against surfaces 51, 58 and.59`

d so pints s2 and s: are yieidinmy contacted by" points 6l. V

IWhen member 60 is caused to ride on surface 59,a point 6| will be brought in contact with point 63. The general construction of this switch orvcircuit closing device 41 is too well known to requirefurther description. It will be understood that the arms to which points 62 and 53 are secured are yieldingly held into position and that lever 68 will be controlled by-surfaces 51, 58 and 59 in a manner too well known to require further description. It will be understood that the members carrying contacts 6|, 62 and 63 are each insulated in their contacts with arm 48 in a manner too well known to require illustration or description.

As illustrated diagrammatically in Figure 6, when members 51and 68 are in contact, no electrical connection will be established and if member 41 is moved in either direction by lever 5|, one or the other of the circuit closing points 62, 63 will be brought in contact with one of the points 6|. Therefore the position of lever 5| will determine the position of the device when the circuit is open and when this lever is moved to the right or left, the circuit will be closed to operate the motor in one direction or the other.

'I'he parts next above described are shown as being operatively connected to the electric battery 18 (see Figure 6) and to the reversing switch D. Point 6| is connected to the storage battery by means of a wire 1| which is shown as being Point.

connected to a stationary switch block 12. 62 is shownas being connectedto a solenoid 13 by means of a wire 14. Point 63 is shown as being connected to a solenoid 15 by means of a wire 16. Switch D is mechanically connected (not shown) to solenoids 13 and 15, and is provided with switch blocks 12, 11, 18, 13, 8| and 82. One end of a field coil of the motor is suitably connected to switch blocks 18 and 8| and the other end of this coil is connected to switch blocks 18 and 82.

I provide a solenoid 83 having an operatingv Solenoids 13 and 15 are each grounded as at I 92. By removing sector 56 so members 6| and 62 are in contact, solenoid 13 will act to move switch D to the position shown which will turn the motor in one direction and when points 6| and 53 are in contact, solenoid 15 will act to move the switch to a position which will cause the motor to turn inthe other direction.

Clearly the motor may be turned in either direction by moving lever 5| so as to cause member 60 to contact either member 58 or 59 and when the motor moves member 28 far enough to bring member 34 in contact'witheither member 32 or 33, member 56 will be turned until the circuit isibroken by means 51. l

I have indicated the positive and negative sides of battery 18 by conventional signs and I have indicated by arrows the direction of travel of the current when points 6| and 63 are in contact and the switch is in the position shown because of the action of solenoid 15. When points 6I and 62 are in contact, the switch will be turned so as to bring blocks 18 and 19 into circuit thus to reverse the direction of the current through eld coil 80 and thereby turn the motor in the other direction.

It will be seen that the motor will be caused When solenoidv33 isenergized,

to stop instantly when the circuit is opened. Therefore I ,provide the braking mechanism which holds the motor from turning except when the circuit is closed.

The motor reversing switch D, member I1 and other parts of the electric system are too well known to require further description and too well known' to require more than diagrammatic drawings as in Figure 6.

It will be seen that because of projection 34 and stops 32 and 33, the movement of the lift is not automatically controlled during the first 5 inches of its stroke from its position nearest the motor. The operator can, however, stop or reverse the movement of the device within this range by means of hand lever 5|. During the lastvtwo or three inches of travel, the lift is under automatic control so that no matter how much the lift is expanded, should the operator move the `hand lever, the lift will take up a position corresponding to the position of the lever where it will lock itself automatically until the hand lever is again moved.

Clearly when projection 34 contacts projection 33, a further movement of the device will cause member 60 to contact member 51 and stop the motor. When lever 5l is moved to the other extreme position, the motor will turn until projection 34 contacts member 32. The further movement of member will cause member 60' to again contact surface 51 and stop the motor. It will be seen that there is an extreme movement in either direction of member 20 and medial positions which act automatically in response to lever 5|. The extreme movement of lever 5I is determined by stops whereby the automatic device will act when member 20 reaches the end of its stroke in either direction.

Obviously the space between members 32 and 33 may be increased so as to automatically stop the movement of member 20 just before it reaches its extreme position in either direction. Lever 5| will then act only to start member 20 in a return movement. In this design, lever 5| may be considerably limited in its movement by suitably positioned stops.

My invention resides principally in a means for automatically stopping the reciprocating part of the device when it reaches the extreme end of its movement, for manually starting the device on return strokes, and for stopping and starting the device in and from medial positions.

Clearly many minor detail changes may be made without departing from the spirit and scope of the present invention, as recited in the appended claims. l

Having thus shown and described my invention, I claim:

1. A device of the class described, comprising a frame having mounted on one end thereof an electric motor, an elongated member slidably mounted in the other end of said frame, the end protruding, means on said frame and means on said elongated member whereby operating connections may be made to an anchor and to the thing to be lifted or moved, an elongated screw threaded connection between said motor and elongated member, a motor reversing switch operatively connected to said motor, a current rei versing switch operatively connected to a source of electric supply and to said motor reversing switch, manually controlled means associated with said current reversing switch, motor and elongated member whereby said means will operate automatically to stop said motor and determine the length of stroke of the elongated member in either direction.

2. A device as recited'ln claim 1 including; said motor having a normally engaged brake and means whereby when the motor is operating, the brake will be automatically released.

3. A device of the class described, comprising an elongated frame having an anchoring means and an electric motor secured to one end thereof, a screw threaded shaft rotatably mounted in said frame and being held against longitudinal movement and being operatively connected to said motor, an elongated-member slidably mounted in said frame, one end protruding from the other end of the frame, a screw threaded connection between said shaft and elongated member,l said elongated member having a projection near the contacts said cam on its neutral position, the circuit will beA opened, means whereby when said lever-is moved in one direction, said reversing switch will be operated to cause the motor to turn in one direction and when said lever is moved in the other direction, said reversing switch will be operated to causethe motor to turn in the other direction. i

4. A device as recited in claim 3 including; a brake adapted to normally hold said motor from turning and having means whereby whenthe motor is connected for operation, the brake will be released.

5. A device as recited in claim 3 including; a spring operatively connected to said cam and adapted to continuously urge the cam in one direction.

6. A device of the class described, comprising an elongated frame having an anchoring means and an electric motor secured to one end thereof, a screw threaded shaft rotatably mounted in said frame and being held against longitudinal movement and being operatively connected to said motor, an elongated member slidably mounted in said frame, one end protruding from the other end of the frame, a screw threaded connection between said shaft and elongated member, said elongated member having a projection near the inner end thereof, a slidably mounted rack having spaced projections adapted to be contacted by said iirst projection in advance of the extreme movement of said elongated member, a cam operatively connected to said rack and having a medial neutral surface, a two point switch rotatably mounted onthe axis of said cam, said switch having manually operating means for moving the switch relative to said cam, a motor reversing switch associated with said motor and rst switch, and means whereby when said iirst switch contacts said cam on its neutral position, the circuit will be. opened, means whereby when said cam is moved in one direction, said reversing switch will be operated to cause the motor to turn in one direction and when said cam is moved inthe other direction, said reversing switch will be operated to cause the motor to turn in the other direction, a spring operatively connected to said cam and adapted to continuously urge the cam in one direction, a second spring adapted to yieldingly determine the movement oi' said cam caused by said'first spring.

7. A device of the. class described, comprising an elongated frame having an enlarged end and an electric motor mounted thereon, an internally screw threaded member slidably mounted in the other end of said frame, one end protruding and member will be automatically stopped when it reaches either extreme position.

8. A device of the class described, comprising a frame having a motor mounted on one end and an oscillating member mounted on the other end thereof, a screw threaded shaft forming an operating connection between said motor and oscil, lating member, a, motor reversing switch operatively connected to said motor and a current reversing switch operatively connected to said motor reversing switch, lost motion mechanical operating connections between said oscillating member and said current reversing switch, said current reversing switch having means for manually controlling its position relative to said lost motion connections, and means whereby the travel of said oscillating member in either direction or its position of rest may be optionally determined by the position of said manually 20 controlling means.

OSBORNE H. SHENSTONE. 

